Polymerization of rosin



Patented Apr. 11, 1950 POLYMERIZATION F ROSIN Burt L. Hampton, Jacksonville, Fla, assignor, by mesne assignments, to The Glidden Company, Cleveland, Ohio, a corporation of Ohio No Drawing. Application June 10, 1946, Serial No. 675,828

9 Claims. (01. 260-99.5)

The present invention relates to process for the polymerization of rosin.

Polymerized rosin and its useful derivatives have many advantageous properties over ordinary unpolymerized rosin and its derivatives, such as higher melting points, higher viscosity, greater stability towards oxidation, and many others. The use of zinc chlorides or stannic chlorides as catalyst for the polymerization has been previously proposed but the catalyst'is either left in the product or numerous washings are required for its removal. United States Patent 2,247,399 describes the use of zinc chlorides as a catalyst for the polymerization, but for practical commercial operation at least l of the catalyst is required.

I have discovered that other metal halides described hereinafter are eiiective as polymerization catalysts and that by activating these halides with certain free hydrohalogen acids, smaller amounts of the halides may be employed, and the Washing diificulties of prior processes may be minimized.

It is accordingly an object of the present invention to provide a new process for producing polymerized rosin.

An additional object is to provide processes for polymerizing rosin which employ new catalysts activated or not by means of free acid.

Another object is to provide a process for polymerizing rosin whereby the halide catalyst employed may be readily removed by washing.

A further object is to provide an improved process for polymerizing resin, in which the amount of metal halide employed as catalyst during polymerization is lowered.

Other objects will be apparent to those skilled in the art from the following description.

In the course of my experimental research in the polymerization of rosin, I have found that the iron chlorides and bromides in both valences are efiective polymerization catalysts for gum and wood rosins. The amount of such halide catalyst which is employed may range from about 0.5% to about 10% based on the weight of rosin present, whether as rosin per se or as rosin dissolved in a suitable solvent. The preferred limits, however, are from about 1% to 5%.

I have also found that when the above mentioned iron halides are activated bythe presence of either free hydrochloric or hydrobromic acid, smaller amounts of catalyst may be used with equal effectiveness. Under such conditions, amounts of the iron salts as small as .01% are eifective and for most purposes amounts less than about 1% are satisfactory with amounts between about 0.3% and 0.7% being preferred. Concentrations of catalyst between 1% and 10% may be used with activating acids, but the disadvantages of added cost and greater washing difiiculties resulting from the use of the larger amounts of catalyst are not suficiently offset by the bene-,

fits. Only small amounts of free acid are needed to eiTect the activation, but amounts greater than a mere trace should be provided to ensure continued effectiveness throughout the duration of the polymerization treatment. For most purposes initial concentrations of free acid between about 2% and .5% provide an adequate excess but under less favorable conditions such as those of prolonged treatment greater initial concentrations of around 2% to 3%, or even up to 5% may be needed. It is within the ability of one skilled in the art to determine the desired concentrations under his selected working conditions, in accordance with the foregoing indications. It should be recognized, however, that the free acid should be kept sufiiciently low to avoid undesirable degradation of the material being treated, or of the final product.

The iron chlorides or bromides may be generated in situ, if preferred, instead of employing the halide salts per se. This can be accomplished conveniently by reacting metallic iron or an iron compound such as the oxide, hydroxide, carbonate, iluoride or iodide with hydrochloric or hydrobromic acid. When the activating effects of free acid are desired, the in-situ production of the catalysts should be accomplished by employing enough of the acids or acid-producing materials to convert all of the compounds to the corresponding halides, and to provide some free acid in addition. I

The acid employed for activation of the catalysts, or for their in-situ production, may be introduced as the hydrogenhalide compound or it may be generated in-situ by using materials which produce hydrochloric or hydrobromic acid under the conditions of treatment. Hydrogenchloride-producing compounds and hydrogenbromide-producing compounds are well known to those skilled in the art, but for purposes of example, the following materials are mentioned: chlorine, phosphorous chlorides, phosphorous bromides, benzoyl chloride, acetyl chloride, and other organic acid chlorides or bromides. The reactions which are involved in producing free hydrogenhalides from these and like materials are well understood. Reference may be made, however, to An Outline of Organic Chemistry by Degerring, published in 1941 (4th edition) where typical reactions with aliphatic and aromatic compounds are explained on pages 3'7 and 185-187 respectively.

While the polymerization, either with or without activating acid, may be carried out on the molten rosin, it is preferable to carry it out on rosin dissolved in an inert solvent. Suitable solvents are glacial acetic acid, mineral spirits, benzene, toluene, xylene, chloro-benzene, ethylene chloride, and many other liquids known already to those skilled in the art. Various concentrations of rosin in solvent from about 30% to 100% have been employed with success, and of these, a solution of about 80% rosin has been found to be the most desirable from practical considerations.

Rosin generally contains some oxidized prodnets and upon addition of the hydrohalogen acid or of the hydrogenhalide-producing material, small quantities of water 'are formed. Likewise, when an iron oxide is employed as catalyst, water is formed by reaction between it and the hydrohalogen acid. The removal from the rosin or rosin solution of water from such sources is not essential to effect polymerization, but for producing th more highly polymerized materials it is advantageous to remove such water as well as anywater present as suchin the rosin or rosin solution.

According to a preferred procedure, a solution of rosin is first formed in an inert solvent. A small quantity ofan iron halide or of an oxide of iron is then added. Chlorine, hydrogen chloride, or a material which yields I-ICl is next added in a quantit suificient to producesome free I-ICl. I'he solution is then heated to the desired temperature, which preferablyis around the boiling point of the solution but which may be any temperature between about 50 C. and 165 C., and is heated for a predetermined time between about hour and 100 hours to produce the desired degree of polymerization. The concentration of solvent in the-mass is then adjusted (if necessaryto facilitate washing) and the solution is washed with water to ensure removal of the metal halide catalyst. Acid may be added to the wash water to assist inthe removal where the amount of catalyst employed is much larger than the'preferred range, supra. In case the polymerization is carried out on molten rosin, treating temperatures ranging from the melting point to about 165 C. may be employed, and after the treatment is com pleted the polymerized rosin should be put into solution for washing, and then washed. In either case the washed solutionis next distilled or otherwise treated to separate the solvent. After such distillation or separation, the product is characterized by the presence of loosel combined HCl. This product would present disadvantages in manufacturing various other products therefrom, such as ester gum, etc., in which heating to elevated temperatures is employed. It is therefore desirable to remove the loosely combined HCl. This can be done by bringing the polymerized rosin to temperatures of the order of 250 C. to 340 C., and sparging the heated rosin by passing in steam or other inert gas or vapor to sweep out the liberated I-ICl. Bromine, hydrogen bromide or a material which yields HBr may be used in place of the corresponding chlorine materials, and in the same way.

The product after removal of all of the HCl or HBr will. be found to have a higher melting point and a higher viscosity in solution, and to be more resistant to oxidation than the original rosin.

The following examples are illustrative of the invention:

EXAMPLE 1 1000 parts of WG gum rosin M. P. 76 C., A. N. 167 were dissolved in 250 parts of mineral spirits and 7 parts of FeClaGHzO together with 6 parts of Br2 was added to the solution which was then heated at 140-150 C. for 5 hours. The solution was then diluted with mineral spirits and washed 5 times with hot water. The solvent was removed with steam, the final temperature of the resin being 220 C. R. & B. M. P. 96 C., A. N. 151, Grade I.

EXAlVIPLE 2 400 parts of WG-gum rosin M. P. 76 C., A. N. 167 from which the metals had been removed by an acid wash of the original gum were dissolved in 100 parts of acetic acid and 3 parts of FeClaGI-IzO together with 4 parts of acetyl chloride were added to the solution. The solution immediately turns ver dark (black) on heating which color is dissipated on washing with water. The solution was gently refluxed for 6.5 hours, poured into mineral spirits, washed with dilute H2804 and finally washed three times with water. The resin was steamed gently at 265 C -275C. for one hour. Grade M; M. P. 975 0.; acid number 156.

EXAIVIPLE 3 400-parts of K gum rosin of M. P. 83 C. and acid number 1'70 were dissolved in 100 parts of mineral spirits and 2 parts of ferrous chloride together with 2 parts of bromine added. The solution was heated at 140-150 C. for 6 hours, diluted with'solvent and washed three times with hot water. The solvent was removed with steam, the final temperature of the resin being 210 C. Grade G, R. & B. MQP. 96 0., acid number 163. A sample of the resin was then steamed gently at 270-2800. for one hour. Grade I, M. P. 95 0., acid number 142.

Blank 1 400' parts of WG-gum rosin from which the Blank 2 500 parts of metal free K gum rosin of M. P. 84 C., A. N. 169 were dissolved in parts of mineral spirits and 2.5 parts of C12 added. The solution was heated'at -150 C. for 5 hours, diluted with'solvent and washed three times with hot water. The solvent was removed with steam, the final temperature of the resin being 220 C. Grade H, M. P. 83C., A. N. 170.

From a comparison of these Blanks with the preceding examples it is seen that in the absence of an iron catalyst, and in the presence of free acid, no polymerization is efiected.

From the foregoing examples and explanations, it'will be recognized that the invention in its broadest'aspects relates to the polymerization of rosin in liquid phase, either as molten rosin or as a solution of rosin in a suitable inert solvent, by means of an iron chloride or bromide as polymerization catalyst. In a more limited aspect, the effectiveness of these catalysts is preferably enhanced by the presence, during polymerization, of free hydrochloric or hydrobromic acid. The iron chlorides or iron bromides may be employed as such, or they may be generated in situ by reaction of an oxidic iron compound with hydrogen chloride or hydrogen bromide, or by reaction of an iron iodide or an iron fluoride with either of the acids. In each aspect of the invention the hydrohalogen acid which is employed may be introduced as such, or it may be formed in situ by employing a halogencontaining material which produces the desired hydrogen halide under the conditions of treatment.

It will be recognized that the invention also contemplates the treatment of the polymerized rosin (as produced by any of the forms of the invention just described above), by a Washing step the purpose of which is to remove the catalyst, by a treating step which separates the polymerized rosin from any solvent which may have been employed during the polymerization process, and by a sparging step having the function of removin any loosely-combined hydrogenhalide remaining in the polymerized rosin after the washing and solvent-separation steps.

The polymerization step efiected by the use of the herein disclosed catalysts, activated or not with free acid, may be carried out at the indicated temperatures for periods of time of from about hour to about 100 hours, or for sufiicient time to eifect polymerization of at least some of the rosin. Considerable polymerization, as indicated by the higher melting points of the products of the treatment shown in the examples, can be accomplished in a matter of a few hours, and for most purposes a treatment lasting from about /2 hour to about 30 hours is adequate to accomplish commercially desirable results.

Having described the invention, I claim:

1. The process for polymerizin rosin which comprises the step of treating rosin in liquid phase with a small amount to about 10% of a catalytic material selected from the group consisting of the iron chlorides and iron bromides, in combination with a halogen-containing material capable of providing to the liquid mass at least one free hydrogenhalide selected from the group consisting of hydrogen chloride and hydrogen bromide, the quantity of said halogencontaining material being such that it provides less than about 5% free hydrogen halide by weight of the rosin, said treating step being carried on at temperatures between about 50 C. and 165 C. for a time of between about one-half hour and 100 hours until the melting point of the rosin has been increased.

2. The process for polymerizing rosin which comprises the step of treating rosin in liquid phase with from .01% to about 1% of a catalytic material selected from the group consisting of the iron chlorides and iron bromides in combination with a halogen-containing material capable of providing to the liquid mass at least one free hydrogenhalide selected from the group consisting of hydrogen chloride and hydrogen bromide, the quantity of said halogen-containing material being such that it provides less than about 5% of free hydrogen halide by weight of the rosin, said treating step being carried on at temperatures between about 50 C. and 165 C. for a time of between about one-half hour and hours until the melting point of the rosin has been increased.

3. The process of claim 2 wherein said rosin in liquid phase consists of a solution of rosin.

4. The process of claim 2 wherein said rosin in liquid phase consists of rosin dissolved in a solvent, and the process includes the additional steps of washing the treated rosin solution, thereafter separating the solvent from said solution to recover the polymerized rosin, and sparging the polymerized rosin at temperatures between about 250 C. and 340 C. with an inert gas to remove loosely combined hydrogenhalide from said polymerized rosin.

5. The process of claim 2 wherein said catalytic material is used in amounts of between about 0.3% and 0.7%.

6. The process for polymerizing rosin which comprises the steps of treating molten rosin with from .01% to about 1% of a catalytic material selected from the group consisting of the iron chlorides and iron bromides, in combination with a halogen-containing material capable of providing to the reaction mass at least one free hydrogenhalide selected from the group consisting of hydrogen chloride and hydrogen bromide, the quantity of said halogen-containing material being such that it provides less than about 5% free hydrogen halide by weight of the rosin, said treatment being carried on at temperatures between the melting point of the rosin and about C. for a time between about and 100 hours sufiicient to efiect polymerization of at least some of the rosin; thereafter dissolving the treated rosin in solvent to form a washable solution; washing the rosin solution; separating the solvent from said washed solution to recover the treated rosin; and sparging the recovered rosin at temperatures between about 250 C. and 340 C. with inert gas to remove loosely-combined hydrogenhalide therefrom.

7. The process as claimed in claim 6 wherein from about 0.3% to 0.7% of said catalytic material is employed.

8. A process for polymerizing rosin which comprises the step of treating rosin in liquid phase solely with a small amount to about 10% of a catalytic material selected from the group consisting of the iron chlorides and iron bromides, at temperatures between about 50 C. and 165 C. for a time of between about and 100 hours until the melting point of the rosin has been increased.

9. The process as claimed in claim 8 wherein from about 1% to 5% of said catalytic material is employed.

BURT L. HAMPTON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,263,915 Borglin Nov. 25, 1941 2,298,270 Auer Oct. 13, 1942 FOREIGN PATENTS Number Country Date 314,588 Great Britain July 1, 1929 361,951 Great Britain May 20, 1931 

1. THE PROCESS FOR POLYMERIZING ROSIN WHICH COMPRISES THE STEP OF TREATING ROSIN IN LIQUID PHASE WITH A SMALL AMOUNT TO ABOUT 10% OF A CATALYTIC MATERIAL SELECTED FROM THE GROUP CONSISTING OF THE IRON CHLORIDES AND IRON BROMIDES, IN COMBINATION WITH A HALOGEN-CONTAINING MATERIAL CAPABLE OF PROVIDING TO THE LIQUID MASS AT LEAST ONE FREE HYDROGENHALIDE SELECTED FROM THE GROUP CONSISTING JOF HYDROGEN CHLORIDE AND HYDROGEN BROMIDE, THE QUANTITY OF SAID HALOGENCONTAINING MATERIAL BEING SUCH THAT IT PROVIDES LESS THAN ABOUT 5% FREE HYDROGEN HALIDE BY WEIGHT OF THE ROSIN, SAID TREATING STEP BEING CARRIED ON AT TEMPERATURES BETWEEN ABOUT 50*C. AND 165*C. FOR A TIME OF BETWEEN ABOUT ONE-HALF HOUR AND 100 HOURS UNTIL THE MELTING POINT OF THE ROSIN HAS BEEN INCREASED. 